Ed Miliband pledged to make the housing market fairer for private renters as he fleshed out his One Nation philosophy.
The Labour leader warned that action is needed to prevent damaging social divisions between home owners and those who rent.
His speech to the Fabian Society again saw him seeking to distance his party from some of the most controversial elements of the last Government's record.
He admitted that New Labour was "far too timid" in enforcing rights and responsibilities and "too sanguine about the consequences of rampant free markets".
"By the time we left office, too many of people of Britain didn't feel as if the Labour Party was open to their influence, or listening to them," Mr Miliband said.
Referring to immigration as an example, he said: "I'm proud to celebrate the multi-ethnic, diverse nature of Britain.
"But high levels of migration were having huge effects on the lives of people in our country - and too often those in power seemed not to accept it.
"The fact that they didn't explains partly why people turned against us in the last election."
Mr Miliband added that if Labour wins the next general election, the party will have to find ways of achieving change while tackling a lingering deficit.
New Labour failed to bring about change to make the economy "work for the many, not just the few", he said.
Spelling out his concerns about the housing market, the opposition leader pointed out that 3.6 million households - including one million with children - are now in privately rented accommodation.
The numbers are bigger than in the social rented sector for the first time in almost half a century.
Mr Miliband said Britain must avoid becoming a nation divided between those who own their own homes and those who rent.
"We shall root out rogue landlords, we shall stop people from being ripped off by letting agencies and we want to give new securities to families who rent."
Labour would introduce a register of landlords and powers for local authorities to find and stamp out rogues, he said, while the "confusing, inconsistent fees and charges" system would be simplified and longer-term tenancy agreements would be made possible.
A Conservative spokesman said: "Not once does Ed Miliband answer the tough questions, like how he would deal with the record deficit his Labour government left behind.
"Instead of facing up to the difficult decisions, all Labour offer is more spending, more borrowing and more debt - exactly how they got us into this mess in the first place."